Production of cuprammonium silk by the stretch spinning process



fro/f x V I Q I gm Q Fig-1 July 7 1936. w. OSTERMANN ET AL PRODUCTION CUPRAMMONIUM SILK BY THE STRETCH SPINNING PROCESS Filed NOV. 15, 1929 Patented July 7, 1936 UNITED STATES PATENT OFFICE PRODUCTION OF CUPRAMMONIUM SILK BY THE STRETCH SPINNING PROCESS Application November 15, 1929, Serial No. 407,366 In Germany November 19, 1928 19 Claims.

In the manufacture of cuprammonium silk by the stretch spinning process, it has already been proposed to use a portion of the precipitant over and over again. A certain quantity of the fresh precipitant, for instance acid, flows into the spinning apparatus at the top, whilst the used precipitant enters at the bottom of said spinning apparatus, where it mixes with the fresh precipitant, is enriched with copper and ammonia and flows away at the discharge pipe, after which it is reintroduced into the spinning apparatus from below. The advantage of this method consists in this, that relatively high final concentrations of copper and ammonia are obtained which are worth putting through a recovery process. On the other hand the method has considerable disadvantages. It necessitates the provision of a separate pump and a system of pipes for enabling the precipitant to circulate. In the case of neutral and basic precipitants, cellulose and copper-containing deposits are frequently separated 'out, which stop up the pipes.

These disadvantages are overcome by the present invention which consists in a process which, while using the same quantity of the fresh precipitant as the known process, transfers the circulation of the precipitant into the spinning apparatus itself. According to the invention a portion of the used precipitant is admixed in the spinning apparatus owing to a circulating flow to the fresh precipitant and is again utilized for precipitation and for drawing out the filaments. Only the non-circulating portion of the used precipitant flows away and has to be replaced by the inflow of fresh precipitant. In this way while using only a small quantity of fresh precipitant the desired velocity of flow in the funnel can be maintained and a high concentration of copper and ammonia obtained in the outflowing precipitant, so that it pays to put it through a recovery process.

- ,A further object of the invention is to provide an apparatus for carrying out the process. All spinning apparatus with a casing and funnelshaped'insertions can be used in which, during the precipitation and drawing out of the filaments, the precipitant from the gradually tapering funnel enters into an enlarged part thereof. The enlarged part is provided with holes or slots which establish communication with the interior of the casing. The high velocity of flow at the narrowest part is suddenly reduced at the enlargement and takes the form of a rise in pressure. Under this pressure a portion of the used precipitant flows through the holes or slots into the casing of the spinning apparatus, where it mixes with the inflowing fresh precipitant. The funnel-shaped insertion in which the precipitation and stretching of the filament takes place may be constructed in various ways. A funnel 5 may be connected at its lower narrow end with a perforated hollow sphere which itself merges again into the wide end of a funnel. In another constructional form two funnels may be so arranged with respect to one another that the lower end of one funnel is embraced by the wide upper end of the other funnel in which it is sealed. About at the level of the lower end of the upper funnel are openings in the wall of the lower funnel.

In the accompanying drawing two constructional examples of the apparatus are shown diagrammatically.

Fig. 1 is a longitudinal section through one constructional form having a cylindrical casing I, an inlet tube 2, and a spinning rose 3. In the casing l is a funnel-shaped member 4 tapering to its lower end 5, which merges in a hollow' spherical extension 6 with openings 1, which itself merges in an outlet tube 8 which tapers towards the bottom. The inserted funnel, the spherical part and the outflow tube are blown in a single piece.

Fig. 2 shows a longitudinal section through another constructional form in which parts contained in the cylindrical casing I consist of a lower funnel-shaped part 9 and an upper funnel shaped part 4 inserted therein. Between the tapered end of the upper funnel 4 and the wide end of the lower funnel 9 is a seal Ill. The openings I connect the interior of the lower funnel 9 with the interior of the outer casing I.

The arrows indicate the direction in which a portion of the precipitant entering the spherical enlargement B or the lower funnel-shaped insertion 9 passes through the openings 1 back into the cylindrical casing I, where it mixes with the fresh precipitant flowing in by the tube 2 so as to be used again. i

What we claim is:

1. An apparatus for spinning artificial silk by the cuprammonium stretch spinning process with a flowing precipitant, comprising a cylindrical casing, a funnel-shaped structure within the said casing, an inlet for the precipitant below the upper edge of the said funnel-shaped structure, the said funnel-shaped structure consisting of two funnel-shaped bodies, one above the other, the wider upper end of the lower body embracing the lower narrow outflow end of the upper body, seal- 55 arranged in the lower portion of the casing, and

an insertion member terminating in an outlet tube and mounted in the foot plate of the casing, said insertion member consisting oftwo tapered tubes, the upper end of the lower of said tubes being larger than, and connected with, the lower end of the upper tube, with apertures in the lower tube in the vicinity of the lower end of the upper tube to allow communication-v between the. interior of the insertion and the surrounding casing.

comprising: :a. spinningnozzle, tubular means 3. An apparatus for spinning artificial threads,

comprising a spinning nozzle, a unitary'spinning funnel positioned to receive filaments from the spinningnozzle,th e said funnel having a. section of increased; diameter; intermediate its ends and having apertures. said enlarged portion, a casing surrounding the upper portion of the funnel to a point below the-said. enlarged. portion, and an inlet for liquidin the casing.

4. In the spinning Off; artificial threads, the steps. comprising; flowing precipitating liquid through; a spinning-fiunnelyin the direction of ncrement of 1 the, filaments, flowing fresh precipitatingliquid in the opposite direction in .a vessel surroundingthe funnel, and. continuously removing a small quantityloi the used precipitating liquid as it passes through the spinningfun-nel and adding it directly tothe fresh liquid surrounding the spinning funnel.

5. Apparatus for spinning artificial. filaments, comprising; a'spinning nozzle, means positioned to receive: filaments from the nozzle and guide afstreant o-f' precipitating; liquid in the direction of travel of the filaments, said. means comprising a funnel portion, an outlet tube portion aligned-therewith, and a, sectionoirenlarged crosssectional area near thesmaller end. of; the, funnel and abovetheoutlet tube, the walls ofjsaid; section forming; with said funnel and tube a. substantially continuous passage, acasing surroundme said; funnel and. enlarged section, means to admit, precipitating liquid to said casing below the top; ofsaid funnel, and apertures inthe walls of; said enlargedzfsection whereby a portion of the precipitating liquid flowing through; the. vfunnel may flow: into-thecasing. *6; An, apparatus :for spinning artificial; filaments, comprising a spinning nozzle, a spinning funnel and a. casing surrounding said funnel and having an inlet for precipitatingliquid', said funnel: having a flared;- upper portion; a constricted discharge tube, an enlarged? section between said discharge. tubezand: the: fiaredgportion, and aperturesiin said 'enlarged section, all constructed and arranged .forcausing liquid-to: flow firomwithin the funnel into the casing. 7. Apparatus for spinning artifidialfilament ing surrnundingasaidl upper portion,- the bottom of: thefcasing being fitted tightly around said means, means toadmit precipitating liquid tothe casingqnearf the: bot-tom thereof and an aperture arranged to cause liquid to-pass htomi within said in the said side walls whereby liquid may flow directly from within the tubular means to the. interior of the casing.

' 8. Apparatus for spinning artificial filaments,.

comprising a spinning nozzle, tubular means therebelow including a funnel-shaped portion for receiving a filament from the nozzle and for guiding a stream of precipitating liquid in the direcing the filament, and; guiding; precipitating liquid in the. direction. of travel thereof, constructed and means through said aperture into the vessel.

1-0.: Apparatus for forming artificial filaments, comprisinga: spinning nozzle, a vessel for; precipitatingzliquid positioned below the nozzle; means .to admitprecipitating' liquid to the vessel, and apertured tubular. means, in the vessel, for receivingv the: filament; and guiding precipitating liqpart and provided with openings communicating with the casing, said tube being constructed. and arranged to lead'a portion of the liqui fiowing through the funnel into. the. casing;

12:. An. apparatus for producing; artificial threads according tothe stretch. spinningprocess comprising a casing, means. to admit precipitating liquid to the casing, amember including'a funnelishaped portion; in the casing; said. member being surroundedatits lower end. by a tube having a constricted outlet, said tubebeing tightlyinserted in the bottom of the casing; and being provided with an aperture so positioned and; shaped: as to be adapted to lead liquid; flowing through. the funnel. into the casing;

13; Anapparatusfor producing artificial silk according to the stretch spinning: process; comprisinga casing,- a tube passing. through the end ofsaid casing; said=tube havingra constricted. outlet and being provided with openings communicating with the casing, and1a funnel concentricallyarranged within the casing. having an outlet portion smaller than and extending into the tube, a

spinning nozzle adapted to discharge filaments 65 into said funnel, and means: for sealing the'tube above thesaid' openings. r

14. An apparatus for producing artificial threads according to-the stretch spinningprocess,

the top of the casing, a tapered member inserted in the casing-below the spinningrose, aninlet pipe positioned in said casing: below the upper edge of" said tapered member; a tube. passing through and sealed within the-lower end of the casing,

comprising a casing; a spinning rose arranged at 76 said tube surrounding the lower portion of the tapered member and being provided with holes leading from the interior of the tube to the casing, and a packing arranged above said holes between the tapered member and the surrounding tube.

15. An apparatus for producing artificial filaments according to the stretch-spinning process, comprising a casing, a funnel within the casing, tubular means communicating with the funnel and having an opening below the outlet end of the funnel and smaller therethan, said tubular means communicating at its upper end with the interior of the casing, and constructed and arranged to by-pass fluid from said funnel into said casing.

16. In a device for forming artificial filaments, a spinning nozzle, a tubular conduit positioned to receive the filaments from the spinning nozzle together with precipitating fluid, a casing surrounding said conduit for supplying fluid to the inside thereof and means for admitting precipitating fluid to the casing, said conduit being constricted at its lower end and provided with an aperture for the passage of fluid from therewithin into the casing.

17. In a device for forming artificial filaments, a spinning nozzle, a tubular conduit positioned to receive the filaments from the spinning nozzle ,ogether with precipitating fluid, said conduit having a constricted outlet and having an aperture in its side wall, a casing surrounding said conduit for supplying liquid to the inside thereof, and means for admitting precipitating liquid to the casing so that it flows upwardly past said aperture.

18. Apparatus for spinning artificial filaments comprising a spinning nozzle, a casing, tubular means therewithin comprising a funnel shaped portion below the nozzle for receiving a filament from said nozzle and precipitating liquid from within the casing, an aperture formed in the wall of said tubular means for returning a portion of the liquid from within the tubular means to the casing and means for supplying precipitating liquid to the casing so that it flows upwardly past said aperture.

19. In a device for forming artificial filaments, a spinning nozzle, a casing, a tubular conduit positioned within said casing to receive filaments from said nozzle together with precipitating liquid, said conduit having an enlarged apertured portion intermediate its ends and within said casing and having a constricted outlet beneath the enlarged portion, and means for supplying precipitating liquid to the said casing so that it flows upwardly past the apertures in said enlarged portion.

WALTER OS'I'ERMANN. WILHELM KUMICHEL. WALTER HOFINGHOFF. 

